I am still working on the pin pointing - spent a couple of hours in a well detected area and dug every signal to get the pin pointing down.
Pinpointing should be a breeze on the F75, it's almost surgical most of the time (iron and zinc targets excluded). Just focus on the little mold circle/dot in just in front of where the rod attaches and that's the sweet spot for pinpointing

You can rotate around the target to make sure it's loudest at that point and you'll know the target will be directly in that spot.
hh,
Brian